ST. LOUIS -- The numbers pointed heavily toward the St. Louis Blues' special teams Thursday.

The Blues came in with the NHL's third-ranked power play. The New York Islanders were last on the penalty kill.

The numbers don't lie on paper, and they certainly didn't this night.

The Blues power play won handily, scoring three times on its first four opportunities, including goals by Derek Roy and David Backes on back-to-back shots in the second period of a 5-1 victory at Scottrade Center.

After consecutive losses to the San Jose Sharks and Los Angeles Kings, the Blues turned to a unit that's been a huge weapon in the first quarter of the season.

"We were very effective on the power play," Blues coach Ken Hitchcock said. "We moved the puck, found shooting lanes. I thought all three goals, there was no chance for the goalie on any of the goals."

Jay Bouwmeester and Roy each scored a power-play goal and had an assist, Kevin Shattenkirk had two assists (giving him four points in two games), and T.J. Oshie had two assists for the Blues (19-5-3). St. Louis tied the Boston Bruins with the most home victories; the Blues are 12-1-2 on home ice.

"The thing I'm happiest about is for 30 minutes, we finally saw our game back again," Hitchcock said. "We saw our pursuit game, we got the puck stopped in the offensive zone, created turnovers, we created second and third turnovers, which is our game.

"I thought for 30 minutes, we started to see what we're capable of again. It was nice to see."

The Islanders started a five-game Western Conference trip with their eighth loss in a row on the road; they are winless in eight straight (0-6-2) overall.

"We're a club right now that's not scoring," Islanders coach Jack Capuano said. "We had chances in the first, thought we dictated the play against a really good hockey team. Second period, all of a sudden, bang, bang, bang, and we can't respond.

"Again, we're not a team that's scoring many goals right now."

The Islanders (8-16-5) had the better of the play to open the second period and got a game-tying power-play goal from defenseman Andrew MacDonald, who beat a screened Jaroslav Halak. But Roy and Backes scored 2:31 apart to give the Blues the lead.

"We all know in this locker room that we have to step it up to get out of this slump," Islanders center Frans Nielsen said. "Everybody has to look in the mirror and see what you can do better. Everybody has to do a better job."

Roy, who had the Blues' first shot on goal in the second period at 6:59, deflected Shattenkirk's shot from the right point, stayed with the puck and roofed the go-ahead goal past Anders Nilsson at 7:02.

Roy was determined, because it was his penalty that led to the Islanders' tying goal.

"I was pretty mad about the penalty and they end up scoring on it," Roy said. "I wanted to get on the power play, I wanted to obviously redeem myself, and I had a chance to."

Backes scored his 13th of the season on a wrist shot from the top of the right circle, with Oshie screening, at 9:33 to make it 3-1.

"Backes' shot, you could see it from the bench. [Nilsson] had no chance," Hitchcock said. "He couldn't see it. It was a perfect shot. Nothing he could do on Roy's shot either. [Bouwmeester's] shot was deflected and stuff like that."

Magnus Paajarvi scored the first even-strength goal at 14:59 of the second period, taking a Patrik Berglund pass and sweeping it past Nilsson from tight quarters to make it 4-1.

Bouwmeester scored the lone goal of the first period, a power-play goal on a shot from the point past a screened Nilsson, who couldn't see around Jaden Schwartz at 11:47.

Blues forward Brenden Morrow crashed the net and banged home Roy's backhand saucer feed from the right boards at 13:19 of the third period to make it 5-1.

Blues defenseman Alex Pietrangelo momentarily left the game after blocking a MacDonald one-timer in the first period, and Halak was bleeding from the mouth after a John Tavares shot hit the goalie in the mask early in the second. Pietrangelo returned to the game, and Halak stayed in.

The Blues are 33-9-5 against the Eastern Conference since the 2010-11 season, the best record in the NHL.

After going 1-for-10 the past two games, the Blues were 3-for-6 on the power play Thursday.

"We got back to what we do best: shooting pucks and getting bodies to the front of the net, and that's usually the battles that we win," Shattenkirk said. "We played against two teams [the Sharks and Kings] that pressured the puck a lot there. We kind of overcomplicated things.

"Tonight, we just got back to simple, point shots, getting pucks to the net and winning those 1-on-1 battles."